Article abstract
Nature Geoscience 1, 263 - 267 (2008)
Published online: 9 March 2008 | doi:10.1038/ngeo128
Subject Category: Palaeoclimate and palaeoceanography
Tree rings and ice cores reveal 14C calibration uncertainties during the Younger Dryas
R. Muscheler1, B. Kromer2, S. Björck1, A. Svensson3, M. Friedrich2,4, K. F. Kaiser5,6 & J. Southon7
Abstract
The Younger Dryas interval during the Last Glacial Termination was an abrupt return to glacial-like conditions punctuating the transition to a warmer, interglacial climate. Despite recent advances in the layer counting of ice-core records of the termination, the timing and length of the Younger Dryas remain controversial. Also, a steep rise in the concentration of atmospheric radiocarbon at the onset of the interval, recorded primarily in the Cariaco Basin, has been difficult to reconcile with simulations of the Younger Dryas carbon cycle. Here we discuss a radiocarbon chronology from a tree-ring record covering the Late Glacial period that has not been absolutely dated. We correlate the chronology to ice-core timescales using the common cosmic production signal in tree-ring 14C and ice-core 10Be concentrations. The results of this correlation suggest that the Cariaco record may be biased by changes in the concentration of radiocarbon in the upper ocean during the early phase of the Younger Dryas climate reversal in the Cariaco basin. This bias in the marine record may also affect the accuracy of a widely used radiocarbon calibration curve over this interval. Our tree-ring-based radiocarbon record is easily reconciled with simulated production rates and carbon-cycle changes associated with reduced ocean ventilation during the Younger Dryas.
- GeoBiosphere Science Centre, Quaternary Sciences, Lund University, Sölvegatan 12, 22362 Lund, Sweden
- Heidelberger Akademie der Wissenschaften, Institut für Umweltphysik, Im Neuenheimer Feld 229, 69120 Heidelberg, Germany
- Niels Bohr Institute, Ice and Climate Research, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen, Denmark
- Hohenheim University, Institute of Botany, Garbenstrasse 30, D-70593 Stuttgart, Germany
- Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
- Department of Geography, University of Zürich-Irchel, Winterthurerstr. 190, 8057 Zürich, Switzerland
- Department of Earth System Science, B321 Croul Hall, University of California, Irvine, California 92697-3100, USA
Correspondence to: R. Muscheler1 e-mail: raimund.muscheler@geol.lu.se